Charline Bourgeois-Tacquet’s new film is a hectic, garrulous, breezily agreeable comedy of midlife emotional upheaval, unencumbered by any serious or permanent concern about any of the passion and heartache that it briefly encounters. It’s also a movie that declines to allow its characters to be changed in any way by the excitements and disappointments that life has to throw at them. Léa Drucker carries off the lead with terrifically competent elan; there’s hardly a scene in which she is not interrupted by a call on her mobile, going into bravura walk-and-talk acting on the phone while on the street, arriving at the office or getting into or out of her car.

She plays Gabrielle, a brilliant surgeon – what other sort is there in the movies? – who specialises in maxillofacial reconstruction. Gabrielle is battling budget cuts, scolding her idle interns, doing outstanding work and is heavily reliant on her assistant Kamyar (Laurent Capelluto). At home, she has a tricky relationship with her partner Henri (Charles Berling), whose teen children from his previous marriage she has raised while resenting his ingratitude for this, as well as for his somewhat semi-detached attitude to their relationship. She is also deeply concerned by her elderly mother Arlette (tenderly played by Marie-Christine Barrault) who is entering the twilight of dementia.

But Gabrielle’s life, whose chaos has been more or less manageable so far, is upended when writer and literary journalist Frida (Mélanie Thierry) asks to witness one of her operations as research for a novel: there is a spark between them and soon they are having a passionate affair after some borderline ridiculous secret handholding at a promenade ballet production.

It is only when Gabrielle goes along with Frida to interview a distinguished author that the film comes fully to life. The author is played by a nonprofessional, the Italian novelist Erri De Luca, whose unassuming reticence is the palate cleanser the film needs. It is at his austere home in the Italian Alps that Frida and Gabrielle’s attraction is consummated as the author’s overnight guests, an outcome perhaps secretly predicted by the elderly author, who warns Gabrielle how tiny her bed is.

So is this a crisis In Gabrielle’s life? Is the thing with Frida real? And, if it’s not, has it clouded or indeed annulled her relationship with Henri? The answers to this emerge in a somewhat contrived dinner scene in Turin, where Gabrielle is giving a hugely prestigious lecture and meets a massively talented artist from Japan. There is something a little feeble about the final fade-out to all this, but Drucker keeps it ticking over.

• A Woman’s Life screened at the Cannes film festival